Automatic telephone system



Jan. 26, 1932. F. GoHoREL. 1,842,602

AUTOMATIC TELEPHONE SYSTEM Original Filed April 4, 1925 l'mrenur FernandEni-rural Patented Jan. 26, 1932 FERNAND GHOREL, F PARIS, FRANCE,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO

ASSOCIATED ELECTRIC LABORATORIES, INC., 0F CHICAGO, ILLINOIS, ACORPORATIO OF DELAWARE AUTOMATIC TELEPHONE SYSTEM rg'inal applicationfiled April 4, 1925, Serial No. 20,609, and in France May 15, 1924,Patent No. 1,670,303, dated May 22, 1928. Divided and this applicationled. December 19, 192?, Serial' No. 241,018.'

The present invention relates in general to automatic telephone systemsbut is concerned more particularly with such systems in which the tollor long distance connections are established automatically. One ot' theobjects oi iny invention may be said to consist ot the production of newand improved toll repeater circuits whereby a subscriber can operateautomatic switches in a distant exchange to extend a connection to adesired called line.

In such systems toll charges may be assessed against the callingsubscriber by operating his message register a number of times to assessa line charge when the called party answers and thereafter reoperatingthe registen at stated intervals to assess an elapsed time chargeproportional to the length of the conversation. Accordingly, a furtherobject ot my invention lies in improved circuits for the control of themessage register to assess toll charges.

rloll lines, to be eliiciently used,` must handle tratlic in bothdirections. Therefore each end ot the toll line must be equipped withincoming switches. In the usual practice, a selector is associated withthe incoming rcpeater to handle incoming calls, in which case the numberof selectors must correspond with the number of toll lines. Aconsiderable saving in the number of selectors required can be eil'cctedby the use ot a line switch associated with the incoming repeater forthe above purpose. This line switch may have access to a small number ofincoming selectors or may have access to the regular local selectors.For such use a preselecting line switch is preferable. Accordingly, afurther obj oct of -my invention may be said to consist ot' an improvedpreselecting rotary line switch adapted to work in connection with therepeater hereinbefore set forth, to complete incoming calls from adistant exchange.

Some of the above features ot this invention are claimed in thecopending application Serial No. 20,609, filed April 4, 1925, of whichthe instant application is a division. Aecordingly, only such objectsand features will be claimed in the instant case which are not protectedin the parent application. These features may be found in circuits andoperations of the repeater and associated line switch, and consistchiefly in novel provisions for reversing current over the callingsubscriber-s line by means of a polarized relay connected in a simplexcircuit to the toll line; in a preselecting line switch whose controlcircuit .is closed by a relay operated ov-er a simplex circuit; and inthe operation of a two-stage relay controlling the line switch.

Other objects of this invention will be apparent from the detaileddescription s and claims which follow.

The accompanying drawing shows diagrammatically at R. a repeater, whichcan be used for incoming and outgoing calls, together with itsarrangement for multiple metering the duration ot' a call; it also showsat C a preselecting secondary line switch. This switch comprises a groupci"` two relays 63 and 64, a rotary magnet 71, wipers 7 2-74, and bankcontacts 75-77- The re-lay'Gll is provided with a locking device, whichprevents all its contacts except the contactbS from operating. When therelay 63 is energized, the locking device ot the relay 611- is releasedthus enabling all the contacts of the relay 64 to operate.

At the incoming end the toll line represoi 1ted by the conductors 78 and79 teril'linates in a repeater similar to the repeater R, and thedescription of its operation at the exchange where the line comes in ismade with reference to the apparatus shown at R and C.

An outline will now be given of the operation of the system.

Vhen the calling subscribe-r has been connected to a repeater such asthe repeater R, which serves a toll line, he takes into use an incomingselecting device at the distant exchange over a repeater, suoli R, andasceondary line switch such C. In response to the operation o't thecallingsubscribers numbor dial, the repeater It. at the outgoingexchange transmits current impulses over both the line. leads inparallel. The repeater R at the incoming exchange transforms theseimpulses into other .impulses suitable for operating` the selecting'devices at the incoming exchange. Y

lVhen the wanted subscriber answers, the

`in this circuit.

current in the toll line is reversed and sets in operation the meteringdevice. The operation of the calling subscribers meter is retardedsufficiently long to enable him to ascertain that he has obtained aconnection with the wanted number. 1f the conversation exceeds apredetermined length of time, the calling subscribers meter is operateda second time, ,but a few ,seconds before this second operation iseffected, they subscriber is warned by a special tone `put on his line.

lVhen the calling subscribers instrument has been `connectedoyer yaselector to the repeater R, Ythe relay 6 is energized in thecircuit:battery, upper winding` of the relay 6, fback contact 18,'banlr contact2 of theselector, the `calling subscribers line and instrument (notshown), selector vbank contact 4, back Contact 19, lower' winding ofrelay 6 and ground. Upon energizing,the relay 6 closes .a circuit attheimpulse contact 21. The rela-y 7 isenergized in the circuit: ground,l.winding of vrelay 7, front contact 20, resistance 83 and battery; atthe iront contact ot it puts ground on the ltest contact 3 of theselector bank, thus marking the line engaged and holding the selector inits operated position.

At -the `front contact 23, the relay 7 prepares the circuit of the relay8, at the front contact of26, it prepares the circuit of the in-.fterrupter M1 over the electromaguet 17, and at'the front of 24 itclosesthe circuit of relay `121andof the left hand :winding of relay 13.`Ast-he relay 13 is polarized, it is not operated Upon-energizing, therelay 12 at the bach contacts 39 and 41 disconnects the uepeating coil Tfrom the secondary line switch, and atrthe'front contacts itconnects thecoil'to the calling line. At the' contact the ground on the flead 60 inseries Vwith the relay 14 and the right hand winding oi' the relay 13 isdisconnected and is replaced bythe battery inseries with the resistance22 and the contact 21.

This .battery being connected to the two conductors ofthe toll line,causes the ener-V gizationof a relay corresponding to the relaay 14atthe repeater at the distant exchange over the following circuit:battery, resistance 22, front contact 21, front contact of 40, right,hand winding of the relay 13, winding of the relay 14,.the two windingsof the repeater T iin parallel, the two leads 78 and 79 ot' the toll'li-ne, the two .windings of a repeater similar lto the repeater coil Tatthe repeater iniithe 'incoming exchange such as R, the relay 14, theright hand winding of relay 13, theback contact of 40, back contact 49and earth. Y y

At the repeater at the incoming exchange. the relay l14, onenergizing,"vv closes the front contact of 44, thus establishing thecircuit of relay 15, and at the front contact of 43 it prepares-a loopacross the line of the secondary line switch C. The relay 15 isenergized in the following circuit: ground, back contact of 24, windingof relay 15, front contact of 44resistance 83 and battery. At the frontcontact ot 45 relay 15 puts ground on the test Contact 3 in the selectorbank over the back contacts 25 and 34, thus marking the line engaged at,the selector in the incoming exchange; at the' contact 48 'it closes acircuit over one winding' of the relay 16; at contact .46 it preparesthe circuit of the relay 8; andiinally, at contact 47 it completes theloop across the line otthe secondary line switch in series with the lefthand winding of the relay 16. The directionot the current in the vrelay16 is such that therelay does notopen ate its contacts. y

The secondary preselecting'line switclrC, located at theincomingexchange, the operationY of which will be 'hereafter eXplained,is alwaysset on the line of an idle selector, and, upon the energize-tion of therelays '14 and 15. thecircuit ofthe relays 63 and 64 is closed over:battery, contact 70, windings of the relays 64 and 63, back contact of66, llead 61, back contact of 41, front contactsof43 and'47, winding(left hand) of the relay16, back contact of 27, lead`62,r back contactot'69 and ground'.

Upon energizing, the relay 63 operates a locking device,thusenablingfrelayr64 to actuate all its contacts; at kthe back contactof 65it disconnects ground Atrein the circuit of the magnet 71, and at thefront contact of 65 Iit establishes a locking circuit in series with therelay 64. The relay 64, on energizing, connects the line to theselecting device at 66 and 69, and opens the circuitofthe rotary magnetat 67.

Then the line is connected to the selecting device y(not shown), itscalling relay is energized in series -with the line loop and closes thecircuit of the releasing relay, which-puts ground on the test leadandtest contact 75. By means ot the wiper 7 2,`this lground is connectedto the end 'of the winding of relay 6 4, andthe relay 63, being shortcircuited, releases, while the relay 64 remains energized. rllhe tollline has now been connected across the repeater R over the -selectingdevice in the incoming exchange. .At the outgoing exchange, the relay 14of the repeater Vis also energized in the circuit above described. butthis has no eff-ect because the circuit of relay 15 is open at the backcontact of24. v i

Yv'hen the subscriberoperateshis number dial for the remaining iguresofthe wanted subscribers number, each interruption of the line by thenumber dial causes the relay 6 to open the contact 21 Vand atbackcontact 20 it closes the circuit of relay 8. The latter,'onenergizing, opens the circuit of the left hand winding of .the repeater4T and' suppressestlie cli'ect ol the condenser' 8() on the relay 6during the impulses.

The short circuiting otl the relay 7 having rendered it slow acting, itremains operated during the impulses and the relay 8, after having beenenergized, likewise does not release until atter the train ot impulses.

:it the incoming exchange, the relay 14 re leases each time its circuitis opened at the contact 2l of the relay 6 in the repeater at theoutgoing exchange, and at its contact 43 it repeats those interruptionsin the line ot the selecting device tor the purpose of positioning theWipers of the latter onto the line ol the wanted subscriber. At the backcontact olI 44. the circuit of the relay 8 is closed and the relay onenergizing` prepares at the trout contact ot' 2T a new circuit tor theimpulses, which does not pass over the Winding of the .relay 1b. rlhcshort circuiting otl the relays la and 8 having rendered them slowacting, they remain intheir operated position during the train etimpulses, and then the relay on releasing, connects the repeater' to theline ot the selectingl device and closes the loop over the Winding ofthe relay 16.

`When the Wanted subscriber responds to the call. the current isreversed in the line of the selecting device and hence in the left handwinding ot the relay 16, and this reversal en ergizes the relay 16.Thereupon the relay 16 opens the circuit ot' the relay 8 at contact 50;it short circuits the contact 43 ot the relay 14 at contact 51, and atthe contact 49 it replaces the ground connection by the special batteryB2 in series with the resistance 5i". The voltage ot this specialbattery B2 is greater than the central battery ot the exchange, hencethe direction ot the current in the toll line ia reversed.

This battery reversal on the toll line causes the relay 13 to beenergized at the repeater in the outgoing exchange. The relay '13, onenergizing, at 42 closes the circuit of the relays 5 and 10. Onenergizing, the relay 5 reverses the battery on thc line ot' the callingsubscriber. Thus supervision is obtained. The relay 10, on energizing,closes the circuit at tor maintaining its upper winding energized; atcontact 34'it connects the test lead to the contacts ot' the meteringrelay 9; at contact 32 it prepares a locking circuit tor its lowerwinding; at 31 it opens the release circuit for the magnet 17; and at 35it closes the circuitot this magnet over the interrupter lvll. whichoperates slowly.

lt will be assumed that the wanted subscriber belongs to an exchange forwhich a three minute conversation costs three times as much as a localcall` In that case the bank contacts of the apparatus, which hascontacts, are connected in multiple as shown in the ligure, and theinterrupter M1 closes its contact every 7.2 seconds. As the meterii'igrelay 9 is connected to the fourth,

sixth and eighth bank contact, the lirst operation of the subscribersmeter is delayed for about 20 seconds, thus giving the callingsubscriber time to release the connection betere metering it for anvreason he finds he is not connected to the wanted party.

lWhen the Wiper 54 reaches the fourth bank contact, the relay 9 isenergized in the following circuit: ground, Wiper 54, fourth bankcontact, lead 58, back contact of 37, Winding ot the relay 9 andbattery. On energizing, the relay 9 at its contact 3() replaces theground on the test lead by the special battery B3, for operating thecalling subscribers meter, and at contact 29 it closes the circuit forthe lower Winding of the relay 10.

At the moment this latter circuit is Without etl'ect, as the relay 10 isenergized by its upper winding. When the wiper 54 passes onto the fifthbank contact, the relay 9 releases, which causes the meter oit thecalling subscriber to tall back likewise after having` registered oneunit. At the sixth and eighth bank contacts the meter is again operated,so that when the Wiper 54 reaches the ninth bank contact, the callingsubscribers meter will have registered three units.

By the action ot' the nlagnet 17, the Wiper continues its rotation and,on reaching its last bank contact, it closes the circuit ot' the relay11 over: ground, Wiper 54. 25th bank contact, lead 5G, lower Winding ofthe relay 11 and battery.

On energizing, the relay 11 at its contact 38 puts a. tone on thecalling subscribei"s line to notiity him that his meter is going to beagain operated. i

It the calling subscriber replaces his ieceiver before the wiper 54 forthe second time reaches the fourth bank contact, the line relay (i, infallin g back, opens the circuit of the relay '7, which on releasingopens at 24 the circuits of the relays l0, 12 and 13, and at the backcontact of 2? prepares the rele; sing circuit tor the magnet 17. Therelay l0, on releasing, removes at 34 ground from the test lead, therebyreleasing the selecting devices; at contact it opens the circuit ot themag net 17 extending over the contact 26, and at contact 31 it closesthe circuit for automatically operating the magnet 17.

It the Wiper 54 is out ot its normal position, the contact 5b is closedand the circuit ot the magnet 17 closed from battery, the Winding of themagnet 17, the contact 52, the Contact 53, the upper Winding of therelay l1, the back contacts of 31, 23, 20 and to ground. The magnet 17,operating intermittently, advances the Wiper 54 to its normal position,in which the contact 53 is opened and the Wiper comes to rest.

The relay 11 is energized in series with the magnet 17 and puts groundon the test lead ot the repeater over the contacts 36, 25 and 34, thuspreventing the repeater being taken iiitouse before the wiper 54 reachesits normal position.

The relay 12, on releasing, connects the toll line tothe secondary lineswitch, and at contact it again puts ground on the lead 60 in serieswith the relay 14. At the incoming .exchange the rela 14 releases whenthe iela leases when the circuit of its lett hand winding is opened at43, and when it has fallen back, ground is again put on the lead inseries with the relay 14.

It the calling subscriber hangs up his receiver while metering is takingplace, the release oi' the switches at the incoming exchange takes placein the inanner above described, but at the outgoing exchange relay 10remains locked untilthe metering has been completed. Thereby its lowerwinding is connected to the tiit'tli and seventh banlr contacts over thefront contact of 32, and from the fifth to the eighth contact thecircuit of its lower winding is closed either at contact 29 or by thewiper 54.

When the calling subscriber has hung up his receiver the relays 5, 6, 7,12, and 13 :t'all back as in the case described above, but the precedingselecting devices are not releaset, because ground or special battery B8is connected to the test lead at the contacts 30 and 34. lvhcn the relay7 falls back, the circuit or' the rotary magnet 17 is connected to theinterrupter M2 at the back contact of 26. This interruptor operatesquicker than the iiiterruptci M1. Accordingly, the magnet 17 operates atsuch rate that the wiper 54 moves too fast for the meter to operate whenthe wiper passes over the metering contacts. The circuit of the lowerwinding of relay 1() is opened when the ninth bank contact is reached,and upon falling back, the relay causes the wiper 54 to stop, asdescribed in the preceding case, in its normal position.

It the calling subscriber shouldhang up his receiver before metering hascommenced, the magnet 17, in ope ating automatically, returns the wiper54 to its normal position, and the relay 11, on energizing in serieswiththe magnet, opens at 37 the circuit ol' the meter ing relay7 9 iiiorder to prevent itsoperation when the wiper 54 passes over the meteringcontacts. Y

The function of the secondary switch C is to connect the toll line, towhich it belongs, with the line of an idle selecting device ,hence whenthe'line, on which the wipers 72, 73 and 74 are standing, is taken intouse, ground is placed on the test lead and test contact, such as thecontact 75, and the test wiper 72 connects .this ground tothe winding ofthe relay 64. On energizing, the relay 64 -only operates the contact68'owing to theloclring 'device,vand the circuit of' the magnet 71'isclosed as follows: earth, back contact of 65,

back Contact or' 67, front contact ot 68, winding of the kmagnet 71 `andbattery. The magnet 71, on energizing, opens at the circuit .63 is notenergized because it is short circuited by ground on the test wiper;hence the relay cannot `be energizedk unless the wipers are standing onan idle line.

It the wipers are standing on an idle Aline f when the switch is takeninto use by a :toll

line, the 'relays 63 and 64 are energized in series by the loop overthetwo leads of the line Gland 62, and in that case the relay 64, beingunlocked by the relay 63, operates all its contacts,'and the switchoperates iii the manner already described.

What is claimed is:

1. In an automatic telephone system, a toll line terminating in arepeater, a calling line,

ineans'for connecting said calling line Vwith said repeater, means insaid repeater operable from said calling line to extend a connectionover said toll line to a called line in a distant exchange, a polarizedrelay in said repeater,

a circuit for said relay including the two sides of said toll line inparallel, means operable by the response of the called party to reversethe 'current flow in saidA circuit, said polarized relay responding tosaid reversed current, and means controlled by said polarized relay forreversing the current flow in said callingline.

2. In an automatic telephone system, a toll line terminating in arepeater, a calling line, means for connectingsaid calling line withsaid repeater, means in said repeater operable from said calling line toextend a coniiec tion over said toll line to a called line in a'distantexchange, a. polarized relay in saidrepeater, a circuit for said relayincluding the two sides of said toll line in parallel, 'means operableby the response of the called party to apply booster battery to saidcircuit in the opposite direction to reverse the current flow therein`said polarized relayresponding l to said reversed current, and meanscontrolled by said polarized relay for reversing the current `flow insaid calling'line.

[n a telephone system, a calling `line,`a called line, a repeater, meansin said repeater for extending a connection from said .calling line tosaidv called line, a polarized relay in said' repeater, a circuit forsaid relay extending over an intermediate section of said connection andincluding two Vtalking conducall) tors oi' said section in parallel,means operable upon the response of the called party for reversing thecurrent liow in said circuit to operate said relay, and means controlledby said relay for reversing the current flow 1n said calling line.

4. ln a telephone system, calling and called lines, switching means forextending a connection from a calling to a called line, a relay in saidswitching means, a circuit ior said relay extending over an intermediatesection ot said connection and incliilding two conductors thereof inparallel, means operable upon the response of the called party 'forreversing the current flow in said circuit to operate said relay, a ndmeans controlled by said relay for reversing the current flow over saidcalling line.

5. In a telephone system, calling and called lines, switching meansincluding a polarized relay for extending` a connection trom a callingto a called line, a circuit for said relay extending over anintermediate section of said connection and including` two conductorsthereof in parallel, means operable upon the response of the called linefor reversing the current flow in said intermediate section to operatesaid relay, and means controlled by said relay Jfor reversing thecurrent flow in said calling line.

(l. ln a telephone system, calling and called lines, a two conductortrunk line, switching means including,` a polarized relay for extending,a connection from a calling` line to a called line over said trunk line,a circuit for said relay including 'the conductors of said trunk line inparallel, means operable upon the response of the called line forreversing the current flow in said trunk line to operate said relay, andmeans controlled by said relay Jfor reversing the current flow in saidcalling line.

7. ln an automatic telephone system, a toll line terminating in arepeater, a line switch associated with said repeater, said line switchbeing` arranged so that it is always in engagement with an idle trunk, aloop circuit for said line switch, means in said repeater operable overthe two sides of said toll line in parallel for closing said loop, andmeans in said line switch operable in response to the closure of saidloop to seize said idle trunk.

8. In a telephone system, a two-way trunk line havingl each end thereofterminating in a repeater and a non-numerical trunk hunting switch,respectively, at each of two exchanges, means at each end of the trunkfor seizing` it to extend a connection from a station in one exchange toa station in the other exchange, and means operated over the twoconductors of the trunk in parallel to cause the trunk hunting switchthereat to automatically extend the connection to a numerical switch.

9. ln a telephone system, a two-way trunk line havingeach end thereofterminating in a repeater and a non-numerical trunk hunt- FERNANDGOHOREL.

